A reaction is said to be of first order if rate of the reaction depends upon one concentration term only. For the reaction A → Products
Rate of reaction α[A]
For the reaction, 2A → Products
Rate of reaction α[A]
For the reaction, A + B → Products
Rate of reaction α[A] or [B]
Consider the simplest case viz
A → Products
Intergrating both sides
Substituting the value of ‘I’, the equation becomes,
where [A]0 is the initial concentration and [A] is concentration of the reactant at any time ‘t’. If the initial concentration of reactant is ‘a’ and amount of reactant reacted is ‘x’ in time ‘t’, then
The exponential form of the expression for first order reaction is
A = A0 .e−kt
